But what we have is the first picture of a bumping race actually happening -

Bumps Serres 1821
Bumping Race at Oxford, signed by John Thomas Serres (1759-1825), dated 1821

Taunt photographed a print of an almost identical picture and assigned it to John's father Dominic Serres (1722-93) thus causing some confusion about the earliest dates of the bumps.
That same picture is in Sherwood's 'Oxford Rowing' dated as 1822.
The barges with sails up on the far bank are presumably travelling through and have been asked to make way for the race. Notice the primitive state of the moored barges - which have not yet reached their final glory at this date - indeed they may not strictly be college barges - but belong to boatmen. The barge with the windows rather like a railway carriage was owned by the boatbuilder Isaac King, and was known as King's Barge. It served as the finishing post for bumping races and it became the custom to indicate the results of each day's racing by the order of flags raised on the barge flagpole - they can be seen above. It became used as changing rooms by the oarsmen and this led to the wish of every college to have its own barge.
John and Stephen Salter took over the barge in 1852 for their own boatbuilding business, before eventually acquiring the Boat House Tavern at Folly Bridge.

1822: HEAD OF THE RIVER - Brasenose
The result was disputed by Jesus and eventually re-rowed -

Brasenose caught a crab and were bumped, but rowing on came in first and claimed to remain 'head'. It must be remembered that the rules were so far only in process of formation, for, of course, now such a claim would be quite inadmissible. This led to a 'confusion of opinion', the Jesus men hoisting their flag as head and the Brasenose men hauling it down again.
The dispute was finally stopped by one of the Brasenose crew remarking:
Quot homines tot sententiae. Different men have different opinions, some like leeks and some like onions
The point of the latter part of the remark being that the Jesus boat had leeks painted on their oars.
It was finally agreed that the race should be rowed again, when Brasenose retained their place.
This somewhat comic incident had however a tragic ending, for the rival crews celebrated their reconciliation by a picnic at Nuneham, when one of their number, T Musgrave of University College, was drowned.

1823: NO RACES
This was possibly the result of an ongoing dispute about the use of watermen as oarsmen.

Sherwood, in "Oxford Rowing, 1900, quotes Gresley in 'Portrait of an English Churchman' describing the start of the races -

Gresley, who took his degree in 1823, and had himself rowed in the Westminster boat before coming to Oxford, in his 'Portrait of an English Churchman' thus describes the start of the races:
His hero and his friend had taken refuge in Iffley Churchyard, to which they had crossed that they might avoid the groups which were assembling to witness the boatrace.
Here the well-known sound of oars arrested their attention, not

The splash so clear and chill
Of yon old fisher's solitary oar

which is described by the poets, but that quick, regular, business-like stroke, which is caused by the rapid turning of many oars at the same moment of time.
Presently a gallant eight-oar appeared in the bend of the river, ... and then another boat succeeded, and another. They entered the lock together, and for a short time all was hushed in silence.
Soon the creaking of the opening gate was heard, and the boats sprang forth one by one ; the sky was rent by the mingled shouts of the friends of each party, as they followed them along the bank, cheering them on in the race, until as they approached towards Oxford the sound died upon the breeze.

In the earlier years of that decade the half-dozen boats that competed were placed in order in the lock at Iffley, with their oars shipped. At a signal the lock was opened, and the captain of the first boat, standing in the bows, fended off the boat as he ran down the gang-board, and dropped into his seat in time to give the stroke as the boat emerged from the lock gates, to be pursued by the next boat as soon as it had completed the like process. In Gresley’s work, the ‘Portrait of a Churchman,’ he makes a very picturesque use of the effect produced by the gradual increase in volume of sound, the measured plash of oars, and deepening chorus of vociferation, as boat after boat emerged into the race.

1824: HEAD OF THE RIVER - Exeter.
This was the last year in which the bumps started out of Iffley Lock.
The Boat Race - An Oxford Scene, from the Literary Lounger (1826, but refers to a lock start) -

SCENE I. — The Lock at Iffley, and the Banks of the Isis up to Oxford.
Crowds of Gownsmen. — "Hines [lock-keeper], open the lock".
"They come!"
(Vast deal of cheering.
Exeter, Christ Church, Black Exeter, and Worcester are the four boats for the race.
Skiffs ; two, four, and six oared cutters in all parts of the river.
The togati, on the banks, preparing for the run.
Eyes anxiously looking for the start;
a beautiful evening between eight and nine;
bustle and life the predominant feature.)
Hines. — "Gentlemen, all ready. Please to want any thing."
Cockswain. — "Grease, and plenty of it."
(The oars being anointed, the boats float out of the lock.
Exeter having the start, then Christ Church, Black Exeter, and Worcester.)
A gownsman on shore — "Are you all right."
"Yes, fire away," from the boat crews.
(A pistol goes off, and the boats at the same time.
Gownsmen hurrying along the banks.)
Cries of "bravo, bravo, go it Christ Church ; you are gaining ground". (Strange phrase at a boat race.)
"Pull, Exeter ; stronger yet ; they gain ; she is almost upon you."
"Huzza! Christ Church, beautifully pulled."
Here a gentleman tumbles in the water, exclaiming, " Holloa! look here." ("Yes, Sir, you seem to be very much in for it.")
(Many knocked up, others dropping the chase, and all puffed.)
"Huzza, huzza, Christ Church for ever."
"Go it, Exeter ; no use ; she beats;"
"bravo! Christ Church bumps her. Huzza!"
(loud cries of exultation for Christ Church.)
Exeter looks exceeding glum and exclaims, " What a sell!"
(Christ Church receives the congratulations of her well-wishers, and then they row direct for Oxford.
The river now exhibits a truly splendid appearance.
All the smaller boats, tugging to arrive with first intelligence, rowed by some of the finest young men in Europe.
The St. John's four oar appears ; abuse follows ; "shame bow; sluggish bow; yah! muffs!" and such like epithets are applied to the attempts, while the regular good ones are hailed with cries loud and lasting.

1825: HEAD OF THE RIVER Christchurch
Bedford, writing in 1895, recalling the first half of the 19th century in 'University Rowing fifty years ago' says -

Boat racing at Oxford became gradually more systematic between 1826 and 1836.
In 1825 the races started above, not in, the lock. As the reason given for this change was that there were now too many boats now racing for them all to get into the lock together, either our records, which only give four boats, must be incomplete, or three boats must have been the limit of the lock's capacity.
The method of starting was now changed. The boats were arranged at intervals of fifty feet apart. A stick, afterwards painted in the college colours, marked the position of each boat, and an umpire, or in latter days three umpires, was appointed to see that each was in its place. Wyatt, the lock-keeper, stood in the middle and asked, "Are you ready?" and it was only on getting "Yes" from all the umpires that he fired his pistol.
The term "Torpid", as applied to second boats, seems to have arisen about this time, but it was not until a later date that the Torpids had races separate from the Eights.

1826: HEAD OF THE RIVER - Christchurch
Rules regulating races were drawn up by the strokes.
1827: HEAD OF THE RIVER - Brasenose
Queen's College launched their first eight.

Some two hundred boats of various kinds were on the river during the races waiting the event. On other nights there were generally private matches of two and four-oars and skiffs. There were also sailing boats, but they were seldom used in the evening on account of the danger, as so many small boats were out.

1828: HEAD OF THE RIVER - Christchurch
"The Episcopal Watchman" (American) in 1828 -

The banks of the Isis presented this evening a most joyous and animated scene. Just before sun-set, the students had assembled by hundreds along the river, to the south of Christ Church Walk, to be the spectators of a rowing match between the elite of Exeter and Brazen-nose.
Large parties had gone half a mile down the river to catch the earliest glimpse of the rival boats; others were distributed about in groups, or stood along the green margin of the stream; and all appeared to enter, with the joyousness and animation peculiar to youth, into the spirit of the contest which was about to be decided.
At length, when expectation was at the highest, "a shout, loud as from numbers without number", from the throng which covered a bridge at the farthest verge of the plain, announced the appearance of the boats ; and in a few minutes they came flying through the water in very gallant style.
First came the flower of Brazennose, in a pearl-coloured, eight-oared cutter, each rower stripped to his shirt sleeves, and resplendent with the yellow badge of his college. A few feet astern followed the youth of Exeter, decorated with a crimson scarf, in a cutter of dazzling white, and impelled by the same number of oars.
The cheers of the spectators made the welkin ring ; and old father Isis, vexed in his deepest recesses by the sturdy strokes of the oarsmen, dashed his waves indignantly against the shore. A prize at the Olympian games could not have been contended for with a more ardent spirit of emulation.
By some mismanagement on the part of the Brazennose steersman, they almost lost the little distance they had gained ; and the cutters came out so nearly equal that it was decided to be "all but a bump".
To add to the spirit and joyousness of the scene, groups of ladies were hovering about in the walks at a distance ; and the river was thickly bestudded with beautiful little two-oared shallops.
These trials of speed frequently take place during the fine part of the season, and afford a manly and unexceptionable recreation to the students.
The Isis, which is here five or six rods wide, and rolls placidly through the meadows, presents every desirable facility for such exhibitions.
I think I have already remarked, that the young men of this country have an appearance of greater muscular strength and capability of bodily exertion, than those of the United States. I speak now of the class which is usually found at seats of learning. They use far more vigorous exercise than the pallid students of our American colleges; and are in consequence much less frequently the victims of debility, dyspepsia, and all the abhorred train of ills, mental and bodily, which result from a too sedentary life.
The beautiful pleasure grounds attached to many of the colleges, offer tempting inducements to quit the cells of study for recreation, during the allotted leisure hours.
"Christ Church Walk" is one of the noblest promenades I have ever seen. It is a walk of hard gravel, forty feet in breadth, lined by a double row of most majestic elms, and nearly half a mile long. It is quite on the south side of the city, and opens into the extensive meadows traversed by the serpentine Isis.

For the first time an Oxford crew, Christchurch, left home waters and challenged Leander to row them on the Tideway. They came to regret it -
Report in the "Sporting Magazine" -


This match, which was for 200 sovs.[sovereigns], and which had caused so much talk among the water-amateurs of London and the men of Oxford, took place on the 27th of last month [June 1828].
The Collegians came down some few days before, for the express purpose of challenging any eight Gentlemen of the lower part of the River Thames to row them a specific distance. It, however, struck them that it would be as well to make inquiries as to the respective "pulling qualities" of the men who were likely to be picked for the purpose. This having been done, the result I should conceive was rather different to what they had anticipated, inasmuch as the furor for the contest was reduced to an aversatio to compete with individuals against whom they found (though almost too late) they should have no chance. On several occasions after this, the Londoners threw out hints which could not be mistaken, but for some time it was "no go".
At length, one evening when the coxswains to the Arrow and Leander, the former a four-oared wherry, the latter a six-oared cutter (each of London), and the coxswain of the Christchurch (Oxford) were shewing their respective boats, some chaffing took place between them; the result of which was, that the next afternoon, when the boats were lying off the Star and Garter, Putney, a message came from the Christchurch men to Mr. Slater (the leading member of the Leander) requesting an interview. This was granted, and a great deal of discussion took place; in the course of which Mr. Slater said, that at present the London men had no eight-oared boat of their own worth any thing, but that they had no objection to row the match, the distance proposed, from Westminster bridge to Putney, in a boat which had been built by Honey and Archer for Trinity College, notwithstanding she had been sent back by them, not "being worth a d-n!".
Or, if they were not satisfied with that proposition, he (Mr. Slater) would pick out six men, four men, or even a pair, who should pull against them for any sum they pleased to name, so anxious was he that a match should take place between some of the parties. It was, however, eventually decided, that an eight-oared match should be rowed on the 27th, and that the Trinity boat should be that in which the Londoners were to do their best, for the honour of the Metropolis.
It must be here remarked that these eight Londoners had never rowed together before, and therefore, not having so good a boat as their opponents, laboured under every disadvantage.
At half-past one o'clock on the 27th the two boats were at their respective stations, at Westminster Bridge, the Trinity being steered by John Mitchell of Strand Lane (the coxswain to the Arrow), and an amateur officiating for the Oxonians.
The London men selected on the occasion, though not including what may be called the whole strength of the Amateurs on the River, were possessed of such power as to render it next to an impossibility that persons accustomed, as the Oxonians, are to "short distances", should head them.
The names were:
Mr. Bayford. - Mr. Henesy.
Mr. Bay ford, jun. - Mr. Howse.
Mr. Bishop. - Mr. G. Lewis.
Mr. Cannon. - Mr. C. Lewis.
Each party, it seems, just before starting was confident of success, but the current betting was 5 and 6 to 4 on the Londoners.
The signal gun was no sooner fired than off went the boats. In a very few strokes the Londoners headed their opponents by No. 1 oar (about three feet). This slight advantage being noticed by their own coxswain, as well as those friends who were near, was hailed as the omen of victory; and
"Now, gentlemen, now's your time - keep it on steadily," from Mitchell, and the continued cheering from those in other boats, acted as a stimulant too strong to allow them to relax in their efforts; and they consequently continued to gain way until they had made a boat's length a-head.
In addition to the pride a man feels in honorably vanquishing an opponent, in this instance the honour, as far as rowing was concerned, of the greatest city in the world was at stake; and I am persuaded that not a man was there in the London boat but what had that sensation or feeling strongly pervading his breast. Notwithstanding, I think, that several, if not the whole, of the Oxonians were born in, or in the immediate vicinity of the metropolis; yet the graduating mania (if I may be allowed the expression, without intending the least offence) of a certain ancient city in the county of Oxford was such as to induce the eight "men" of Christchurch to endeavour to wrest from the Londoners those laurels which had been so long and so trinmphantly worn by them without molestation.
After a hard contest, the match was decided by the Londoners going through Putney Bridge about seventy yards a-head. There was an immense mass of spectators, though not so many as there would have been, had it been generally known that the day in question was the one selected. The victors were hailed with the most enthusiastic plaudits of the multitude.

However a very significant year. Having had fingers burned in challenging Leander, Oxford looked around for what they thought might be more level terms, and lighted on Cambridge.
The first Oxford versus Cambridge Boatrace took place at Henley
See Boat Race pages for a full account.

The Oxford Boat Race Crew of 1829 -

Oxford Crew of 1829
The Oxford Boat Race Crew of 1829

The Oxford 1829 boat was 47 feet long and 4ft 5 in wide
Just 22 feet longer than my punt and almost twice as wide! -

Oxford 1829 Boat
Oxford 1829 Boat and 1929 Boat